Mercury circuit breaker



May 12, 1959 J. NAWOJSKI 2,886,662

MERCURY CIRCUIT BREAKER Filed July 25, 1957 INVENTOR. JUL/US Mara/SKI United htates Patent Q MERCURY CIRCUIT BREAKER Julius Nawojski, Roseville, Mich.

Application July 25, 1957, Serial No. 674,215

3 Claims. (Cl. 200-32) The invention relates to a breaker in the ignition system for internal combustion engines of the type generally used in automobiles.

As is well known, the conventional ignition systems used in auto vehicles includes a primary or low tension circuit, a part of which is a primary winding of an induction coil, and a secondary, or high tension circuit, a part of which is the winding of a secondary or high tension coil. It is the secondary coil which is connected to the spark plugs of the internal combustion engine and in which high voltage sparks are generated by disruption of the primary circuit. A mechanical device which is generally used for the purpose of breaking the primary circuit includes an arm known as the breaker arm, which is actuated by a rotary cam and which intermittently comes into contact with a stationary point or terminal of said primary circuit.

In time, the contact areas on the arm and on the terminal point become oxidised and pitted so that the efficiency of the mechanism is impaired, and when the contact elements on the circuit disrupting members have to be replaced.

It is therefore the object of this invention to provide a circuit breaker immune to the above deteriorations. A further object of the invention is to provide a breaker, fully practical and reliable, but small enough to fit into the casing of the distributor included in the ignition system in which the conventional circuit breaker is located.

The breaker described by meincludes a quantity of mercury as a current conducting element and while mercury circuit breakers in general are already known in art the breaker designed by me has the advantage of simplicity, compactness and general efficiency in operation.

I shall now describe my improvement with reference to the accompanying drawings in which:

Fig. l is a top view of the circuit breaking mechanism as mounted with the casing of a conventional distributor of the kind used in internal combustion engines in automobiles, the view including the circuit breaker of my invention;

Pig. 2 is an enlarged sectional view of the circuit breaker of my invention;

Fig. 3 is a sectional view on line 33 of Fig. 2;

Fig. 4 is a sectional view on line 44 of Fig. 2;

Similar numerals refer to similar parts throughout the several views.

In the drawing in Fig. l, the housing of the distributor is marked 10. The circuit breaking mechanism base plate 11, the mechanism including a rotary cam 12 mounted on a shaft 13, a breaker arm 14 provided with a bumper block 15 which bears against the cam, and a spring 16 which urges the arm against the cam. The arm 14 is equipped at its operative end, with a contact element or point 17. The circuit breaker of my invention, secured to said plate 11, in opposed relation to said arm, 18 generally identified by numeral 20.

The breaker itself includes a cylindrical casing 21, the casing being closed at one end by an integrally formed end wall 22 but being open at the other end. Said other 2,886,662 Patented May 12, 1959 end is threaded internally as shown at 23 for reception of a threaded plug 24 which is provided with an axial bore 25. Integrally formed with the cylinder 21 and extending therefrom in a substantially tangential relation thereto, but in opposite directions, are two flanges 26, these being provided with holes for reception of screws 27 by means of which the casing may be secured to said plate 11.

internally the casing is divided into two chambers by means of a thick partition 28. The partition, made of dielectric material, bears against an inner shoulder 29 within one end portion of said casing. One of the chambers, defined in part by the end wall 22, is marked 30; the other, and a larger chamber, is marked 36a. The partition contains an axial bore 31, which flares outwardly on the side facing the end wall 22, the flared out portion of the bore having the form of a funnel 32, as shown in the drawing. Running parallel to the bore 31, is a duct 33 of a restricted diameter, the duct opening at one end into the funnel shaped cavity 32 while the other end of the duct opens in the direction of the larger chamber 30a.

Located within the axial bore 31 in the partition 28, for a longitudinal sliding movement therein, is a shaft 34 which also is made of dielectric material. One end of the shaft extends into the chamber 30, and it is at this end that the shaft carries a frustoconical closure, or valve, 35, which is of a size to fit snugly into the funnel shaped cavity 32 at one end of the bore 31. A spring 36, coiled about the portion of the shaft between the wall 22 of the casing and the closure 35, bears against the said closure, urging it into said cavity 32.

Mounted upon the shaft on the other side of the partition, that is within the larger chamber 30a, is a flexible cup shaped diaphragm 37 of a dielectric material such as rubber, the rim portion thereof bearing against the rim portion of said partition 28. The diaphragm includes an integrally formed hub portion 38, which is tubular in shape and which is clamped to the shaft in a liquid tight manner by a clamp 39.

In order that the outer rim portion of the diaphragm may be held in liquid tight contact with the periphery of the partition, a tube 40 is inserted in the casing 21, the tube bearing at one end against the rim portion of the diaphragm, while at the other end, said tube is in contact with the plug 24. As the plug is threaded into the casing, it is possible by means of said plug, to adjustably exert sufficient pressure against the diaphragm to hold it tightly against said partition.

As shown in Fig. 2, one end 41 of the shaft extends from the casing outwardly, through the bore 25 in the plug 24, for operative engagement with the contact point 17 of the breaker arm 14.

A metal screw 42 threaded through the wall of the easing 28, enters into chamber 30 which is filled with mercury marked 44. Another screw 43, threaded through the wall of said casing enters the duct 33. Each of the screws is provided with an externally located head for connection to a terminal point of the low tension circuit.

A quantity of mercury 44 is also contained with the space between the partition 28 and the cupshaped diaphragm 37, and in the duct 33.

I shall now describe the operation of the breaker.

It will be assumed that screw 42 and the mercury in chamber 30 will form one terminal of the low tension circuit, and that screw 43 and mercury within the duct 33, will form another terminal within said circuit. It will be further assumed that the shaft is in such a position that the closure 35 is disengaged from cavity 32, thus permitting the mercury in the duct 33 to serve as a liquid conductor of electric current between the two terminals. This, of course, would happen only on depression of the shaft inwardly by the breaker arm 14 at the time when one flat U side of the cam 12, intermediate its two adjoining lobes, would be in contact with the bumper block 15. However, immediately thereafter, when the breaker arm would be deflected from the axis of the cam 12, by one of the lobes, the shaft 34, 'actuatedby spring 36, would slide outwardly through the bore 25, and cause the closure 35 to enter said cavity 32, blocking the duct 33 and this would separate the two bodies of mercury, thus disrupting the flow of current therebetween. In the next phase of the operation, the breaker arm returning back in the direction of the axis of the cam, the shaft 34 would be depressed, causing the flexible diaphragm to force a quantity of mercury from the cup 37, into and through the duct 33 for connection with the body of mercury in chamber 3d, thus again closing the circuit.

It will be understood that some changes may be made in the structure of the breaker, described by me without departing beyond the inventive concept disclosed herein. What I therefore wish to claim is as follows:

1. In an ignition system for internal combustion engines, a breaker for an electric circuit, the breaker including a cylindrical case having a closed end wall and a transverse partition in a spaced relation to said end wall, the space between the end wall and the partition forming a chamber, the partition being provided with an axial aperture, expanded on the side facing the end wall into a flared out funnel shaped socket, and with a narrow duct running parallel to the aperture into said socket, a shaft slidingly passing through said aperture towards said end wall, a cone shaped closure on the shaft and within the chamber for entry into said socket, a flexible cup axially mounted on the shaft, the rim portion of the cup bearing against the rim portion of the partition on the side remote from the end wall, a quantity of mercury in the chamber, a quantity of mercury in the interior of the flexible cup and in the duct, spring means upon the shaft to keep the cone shaped closure within the socket to block the duct, the outer end of the shaft extending outwardl3 from the case and being adapted to be depressed against the tension of said spring to move the closure out of the socket to unblock the duct, aterminal of the circuit leading into said chamber, and a terminal leading into said'duct.

2. In an ignition system, a breaker for an electric circuit, said breaker including an oblong casing having one closed end Wall and having a transverse partition spaced from said closed end, the partition being provided with an axial aperture and a duct of relatively restricted diameter passing through said partition, parallel to said aperture, a sliding shaft disposed within said aperture and including a closure mounted thereon and adapted to close said duct, one end of the shaft extending out of the case through the end remote from the closed end, spring means urging the shaft in the direction of the partition to cause the closure to block the duct, the case, the shaft, the closure and the partition being made of dielectric material, a flexible cup shaped diaphragm mounted axially on the shaft and having its rim portion clamped against the rim portion of the partition on the side remote from said closed end wall, a quantity of mercury within the chamber, and within the cup, a terminal for the circuit extending from the chamber outwardly, and another terminal extending from the duct outwardly, the outer end of the shaft being adapted to be depressed against the tension of the spring to unblock the duct and to force mercury from the cup through the duct, to contact mercury in the chamher.

3. In a distributor forming a part of an ignition system for internal combustion engines, and including a reciprocating arm, a circuit breaker adapted to be actuated by said arm, the circuit breaker including an oblong casing having one closed end wall and having a transverse partition spaced from said closed end, the partition being provided with an axial aperture and a duct of relatively restricted diameter passing through said partition, parallel to said aperture, a sliding shaft disposed within said aperture and including a closure mounted thereon and adapted to close said duct, one end of the shaft extending out of the case through the end remote from the closed end, spring means urging the shaft in the direction of the partition to cause the closure to block the duct, the case, the shaft, the closure and the partition being made of dielectric material, a flexible cup mounted axially on the shaft, the cup opening towards the partition on the side remote from the closed end Wall of the casing and having its rim portion held in abutment with said partition, a quantity of mercury within the cup, and within the chamber, a terminal for the circuit extending from the chamber outwardly, and another terminal extending from the duct outwardly, the outer end of the shaft being adapted to be depressed by said reciprocating arm against the tension of the spring to shift the closure away from the duct, and to force the mercury from the cup through the duct to merge with the mercury in the chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,983,150 Sigman Dec. 4, 1934 2,606,256 Sissenwine et a1 Aug. 5, 1952 2,720,562 McLaughlin Oct. 11, 1955 2,802,115 Datesman et al Aug. 6, 1957 

